A magnet is a metallic object capable of attracting iron and certain other metals and alloys. Around every magnet there is a region in which the force of the magnet exists. The region is called the magnetic field. The international unit of the magnetic field is the tesla (T). The strongest lab magnets are permanent, superconducting, and pulsed magnets. Permanent magnets retain their magnetism for a long time. The neodymium-iron-boron magnet is the strongest permanent magnet of our time, which can produce a field of about 0.1 T. Superconducting magnets are a type of electromagnet that produces a magnetic field from the flow electric current through a material with no resistance. A superconducting magnet can reach field strengths as high as 13.5 T. A pulse magnet provides very high magnetic field as high as 72 T.